r200: revalidate after radeon_update_renderbuffers

r200: revalidate after radeon_update_renderbuffers

By calling radeon_draw_buffers (which sets the necessary flags
in radeon->NewGLState) and revalidating if NewGLState is non-zero
in r200TclPrimitive. This fixes an assert in libdrm (the color-/
depthbuffer was changed but not yet validated) and and stops the
kernel cs checker from complaining about them (when they're too
small).

Thanks to Mario Kleiner for the hint to call radeon_draw_buffer
(instead of my half-broken hack).

v2: Also fix the swtcl r200 path.

Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>